1. Field of the Invention
The invention relates to a driving control system for vehicles.
2. Description of Related Art
Motors such as internal combustion engines and electric motors are installed as driving sources, in vehicles such as automobiles. Such motors are coupled to wheels through a transmission. The vehicle is provided with a shift mechanism that allows switching, in response to an operation by the driver, between a driving position (for instance, a position such that the vehicle travels forward, or a position such that the vehicle travels in reverse) and a non-driving position (for instance, a parking position or a neutral position).
An operation lever, as an operation unit of the shift mechanism, is coupled to the abovementioned transmission (specifically, to a shift fork of the transmission). When the operation lever is operated to a driving position, the transmission is brought to an operation state (power transmission state) in which a driving force is transmitted from the motor to the wheels, and when the operation lever is operated to a non-driving position, the transmission is brought to an operation state (power interrupt state) in which transmission of the driving force from the motor to the wheels is interrupted.
In vehicles of a related art, wherein driving force is transmitted from a motor to wheels (Japanese Patent Application Publication No. 2010-18174 (JP-2010-18174 A)), a driving force limitation process for limiting the driving force that is outputted by the motor is executed when an operation position of a shift mechanism is shifted from a non-driving position to a driving position, in a state that the accelerator operation member of the vehicle is operated to the on state. In such a device, the driving force that is transmitted from the motor to the wheels is kept small even in a case where the shift mechanism is operated from a non-driving position to a driving position in a state of increased motor output that results from the operation of the accelerator operation member. As a result, discomfort to the driver resulting from transmission of the driving force can be suppressed, and a decrease in drivability is suppressed.
Shift position sensors for detecting the operation position of the operation lever are ordinarily mounted in the shift mechanism. Such shift position sensors are made up of detection units (for instance, switches) that are respectively mounted in the vicinity of each operation position of the operation lever, The operation position of the shift mechanism is detected on the basis of output signals of the detection units.
In such a position detection device, a state is detected in which, although temporarily, the operation lever is not operated to any of the operation positions, when the operation lever is at intermediate positions between operation positions in the course of the shifting operation of the shift mechanism. In cases where, for instance, the operation lever is operated slowly, such a state may in some instances go on for a comparatively long time, depending on the way in which the operation lever is operated to the respective operation positions.
When a state is brought about in which the operation lever is not operated to any of the operation positions upon operation of the operation lever from a non-driving position to a driving position, the operation state of the transmission that is coupled to the operation lever is brought to a power transmission state, and the operation position of the shift mechanism detected by the position detection device is not a driving position. At this time, the vehicle starts as a result of the actual operation state of the transmission being brought to the power transmission state, despite the fact that the operation state of the transmission, as determined on the basis of the detection result by the position detection device, is still a power interrupt state. Accordingly, the above-described driving force limitation process is initiated, as a result of which the vehicle may stall and drivability decreases, when the operation position of the operation lever is brought thereafter to an adequate position and the position detection device detects that the operation position of the operation lever is a driving position.
In the above-described device, thus, a discrepancy may arise between the actual operation state of the transmission and the operation state of the transmission as determined on the basis of the detection result by the position detection device. Drivability may be impaired on account of that discrepancy.